The present invention relates to an optical detector and amplifier for detecting radio frequency (RF) and microwave signals, in the following also denoted “optical detector for detecting RF signals”, and particularly for detecting weak RF and microwave signals. In this connection weak RF and microwave signal is intended to mean RF and microwave signals having a root mean squared amplitude, Vs, in the μV-range or smaller.
It is noted that as used herein the term “metalize” is intended to be understood in its broadest sense, i.e. in the sense of making an object metallic in form or appearance, irrespective of in which way this is obtained.
The article “Optical detection of radio waves through a nanomechanical detector” published in Nature, Vol. 507, 6 Mar. 2014, by the inventors describes such an optical detector for detecting RF signals, and the corresponding manuscript with the same authors and preceding this article provides further information regarding the theory behind such a device, these two documents hereby being incorporated herein by reference in their entirety.
Optical detectors for detecting radio frequency signals provide a conversion interface between wireless communication and optical communication. RF to optical conversion can be advantageous if the radio frequency signals are to be transferred over long distances, as light can be transported in fibres with much lower loss than radio frequency signals in cables. Furthermore, since optical signals can be detected with quantum limited sensitivity, the converter also provides a means for low noise, high sensitivity and low power consuming detection of radio frequency signals after their conversion.
The article “Bidirectional and efficient conversion between microwave and optical light” by R. W. Andrews et al. and published in Nature Physics, Vol. 10, April 2014, describes an optical detector for detecting radio frequency, and particularly microwave, radiation which comprises an LC-circuit with a position dependent capacitor, and which is operated at cryogenic temperatures of 4 K or lower.
However, the prior art optical detectors for detecting radio frequency signals have the drawback that they require cryogenic cooling to temperatures as low as a few K, or in other words cooling with, e.g., liquid helium. Such cryogenic cooling is very expensive, and the prior art optical detectors are therefore very costly both to acquire and to use.